The present invention relates to integrated circuits used in safety applications and, more particularly, to an ERROR pad for an integrated circuit used in safety applications.
Safety compliant auto devices have a pad to indicate the occurrence of an internal error. FIG. 1 shows a conventional ERROR pad connection in an integrated circuit of a safety device 100 with an ERROR pad 102 dedicated for safety applications. A fault collection and control unit 104 is connected to a data pin 106 of the ERROR pad 102 for collecting and providing error occurrence information to the ERROR pad 102. A plurality of configuration pins 108 of the ERROR pad 102 are tied to predetermined static values, e.g. “0” or “1”, so that the error occurrence information input through the data pin 106 can be output through an output pin 110 of the ERROR pad 102. For safety reasons, none of the configuration pins 108 may be configurable via a memory mapped register, therefore the ERROR pad 102 cannot be multiplexed with other functions. This requirement limits safety devices that cannot afford a dedicated ERROR pad or more than one ERROR pad in a pad limited System-on-Chip (SoC) design. Further, the number of pads that can be used for functional pad multiplexing is also limited by this requirement especially in a safety device with a lower pin count package.
It is desirable that the ERROR pad be available for functional pad multiplexing when not being used as an ERROR pad.